Changes in immune cell phenotypes in response to leniolisib. (A) Frequencies of transitional (left) and naive (right) B cells. (B) Frequencies of senescent CD57⁺CD4⁻ (left) and PD-1⁺CD4⁺ T cells (right). Data are shown as mean values of indicated number of patients with SD. Vertical dotted lines indicate start of leniolisib dosing. The healthy volunteers’ median reference values for naive B cells, transitional B cells, CD57⁺CD4⁻ cells, and PD1⁺CD4⁺ cells are: 74.7%,²⁴  4.7%,²⁴  17%³⁵  and 13.2%,³⁶  respectively. (C) Representative fluorescence-activated cell sorting (FACS) dot blots for patient 3 from panels A and B at baseline and end of treatment.